Air-feed brake



March 30,1926, 4 1,578,997

v G. W. HULSHIZER AIR FEED BRAKE Filed Sept. 16, 1925 e @i v k Y E g P INVENTOR. Gena ell fliddk cz' BY7Z 1.5 ATTO EY' Patented Mar. 30, 1926.

UNITED STATES enonen w. HULSHIZER, or STEWARTSV'ILLE" JERSEY, assreuon TO: rivanrtsoLL-RANDooMrANY, or JERsEYoIrY, new JERSEY, A oonroRAmoNoFi 'Ew, I

j JERSEY;

AIR-FEED BRAKE;

To all whom it may concern."

Be it known that I, GEORGE XVJHULSHIZER, I a citizen of the United States, and a resident of Stewartsville', in the county of WVarren and State of New Jersey, have invented va certain Air-Feed Brake, of which the following is a specification, accompanied'by drawings. 7 I

This invention relates to rock drills; but more particularly to an air feed brake for fluid actuated rock drills of the stoper type. The objects of the invention are to equip the feeding element of arock drill with a brake adapted to be applied by pressure fluid acting against the feeding piston for preventing recoil of the rock drill at the time the hammer piston strikesthe drill steel, to enable such brake to be automatically releasedupon the releasejof pressure fluid from the feeding cylinder and to increase the drilling efliciency of rock drills of the stoper pe. a v 2 l Further. objects will be in part obvious and in part pointed out hereinafter. V

The invention consists of the combinations of, elements, features of construction and arrangement of parts having the general mode of operation substantially as hereinafter described and more particularly point ed out'in the appended claims and illustrated in the accompanying drawings, in "which I I i Figure 1 1s a longitudinal View in elevation and partly in section of ;a rock drill constructed in accordance with the pract ce of the invention, and Y 'Figure 2 is a longitudinal detailview in elevation partly in section showing the manner in which the air feedbrake is applied. Referring to the drawings; a preferred 'niodific-ation of the invention is shown, em-

:bodied in a rock drill of the stoper typehaving a cylinder A and afront head B se cured to the cylinder by means of cushioned side bolts C. A drill steel Dis inserted into the front head, B to receive the blows of'a hammer piston (not shown) reciprocating within the cylinder A. "A back head E forms a closure for the rear end ofthe cylinder Aand has secured thereto a rotation handle To the end that the drill may be advanced toward the work as the drill steel D penei v 578,99 PATENT QF'F 1 trates the rock G, a feeding-cylinderI-I liavg, lnga flange J is secured to ,the'c-ylinderA by means of bolts K, Thebolts K also serve to clamp the back head E betwee'n thecylinders A and H- and thus'hold th'e'cylinders and the back headin operative'position; A

piston rod L is arranged Within the cylinder Hand carries at its outer end a-rock engage ing pointer O' which supports the drill and holds the drill in position. i

invention, a conical extension P is formed v In accordance with the" practice of the a reduced cylindrical-extension Q, which engages slidably a piston R whereby the inner end of said rod is held concentrically with- "in'the cylinder H. Thepiston R "inthis'instanc'e has a bore S,'a portion of which is cone shaped to correspond with the conical extension P so that the piston mayniovc freely longitudinally of said extension, a

springT abutting at one end the conical ex tensionP and at its other end a shoulder U of the piston R tends to constantly force said piston away from the extension P. 'Means are provided for preventing recoil "of the drill from the working face at the time the hammer-piston strikes the drill steel, to this end 'an'annular groove V is formed in the piston Rto receive a-fric-tional member or members W preferably in' the form of fibre segments shaped to conformattheir outer surface with the bore ofthe -,cylinder- H. A plurality of radial holes X are formed in the piston Rto receive plungers Y arranged slidably therein toabut with one end the segments W and-With the'opposite end the conical extension P; t

The piston R in this instance has areducedextension Z to permit a sealing memher in the formofaoup leather 7) to bearranged thereabout 'for the purpose of preventing leakage 'ofpressure fluid between" the pistonR and the cylinder H. A collar 0 is arranged above the extension Z' of thepi'ston to bear-at one end upon the said-cup leather 6 and is held firmly in position by I means of anut (Z screwed on'the end of said extension, 7 t

To the end that the feedingelement may be properly centralized with theback head E, a feeding cylinder 'bushi-ngeis arranged inrthe inner end of the cylinder H to' extend into the back head E and, has a bore 7 through which pressure fluid may pass into the cylinder 'H for causing longitudinal movement between said cylinder and the piston R. In addition to serving as a pas-. sage for pressure fluld therethrough, the

bore f' also serves as a means for frictionally engaging a split spring ring 9 carried by a nut h on the end of the cylindrical extension Q, of the piston rod L. In this way the piston rod L may be securely held against endwise movement while the drill is being transported;

' Pressure fluid for operating the drill is admitted through a suitable connection, into; the back head E and the admission thereof int-o the percussive and feeding elements is controlled by a suitable throttle Valve (notisliown) having a throttle leverk.

Inorder to provide for the release of pressure fluid from the feeding cylinder H in case the-drill steel D becomesstuck. in the drill hole, or if for other well-known reasons it be desired to retard the-feeding speed of the drill, the rotation handle F is pro-. vided' with a longitudinal passage 0 which communicates with the cylinden H through a passage 7) in the back head E, said pas sage p beingin communication with the bore ofthe cylinder H. Suitable controlling means preferably such as are-disclosed in the U. S. Patent No. 1,407,591 granted February 21, 1922,,to F. M. Slater for an air feed controlforrock drills, may be employed, for; controlling the passage 0. Ac-

cordingly,a valve is arranged transversely fluid to the percussive and feeding ele-.

ments,.pressure fluid entering into the feeding cylinder 7H will advance the drill in accordance with the penetration of the drill steel into the rock, and acting againstv the piston R will force said piston outwardly or downwardly alongthe extension Q. Such pressure against the piston. will compress the spring T and cause the plungers Yto force. the fibre ring or. segments W against the wallof the cylinder H and serve as a brake; to prevent recoil ,of the percussive element at the time the hammer piston of the drill. strikes the drill steel. If, for well known reasons, it be desired to withdraw the drill somewhat from the work, pressure fluid front/the feeding cylinder H may be released byv proper manipulation of the.

valve 9; Upon such release of pressure fluid the spring Twill automatically raise the piston R and thus move the plungers Y'out of'contact with the conical extension P and release the pressure against the segments W.

Similarly, if'it be desiredto ceasedr ill-ing operations the pressure'fluidtothe percussive and feeding elements may be shut Off, andby bleeding the air from the feeding cylinder the braking actionof the segments W will be automatically released by the spring T as herein described. The drill, together; with the cylinder 11, may. then be lowered until the spring ring. 9 is forced into thebore f of the bushing 6. Owing to the expansibility of the spring ring; g

of. the drill towards the working face isat all times assured.

I claim:

1. In an air feed brake-for a fluid actuated rock drill, the combination of a feeding cylinderwith a fluid actuated piston, a rod.

for, said piston and slidable longitudinally with respect thereto, a conical extension on said rod, frictional members in said;piston, and radially extending plungers slidable in the piston to abut at one end the. conical extension and to abut at the other, end the frictional members to force said members outwardly against the cylinder and prevent recoil of the cylinder during the operation of the drill when pressure fluid acts against :the piston.

2. In an air feed brake for afluid: actu: ated rock drill, the combination of a feeding,

cylinder with a fluid actuated piston, arod for saidpiston and slidablelongitudinally with respect-thereto, a conicalextension on said rod, fibre segments in said piston, radially extending plungers slidable inthe. piston to abut at one end the conical extension and to abut at the other end the. fibre segments to force said segments outwardly against the cylinder and prevent recoil of the cylinder during the operation of the drill" when pressure fluid acts'against the piston, and a sprlngfor automatically moving the piston longitudinally in one direction with respect to the rod to release the fibre segments upon the release of. pressure fluid from the cylinder. 7

lntestimony whereof I haveisigned this specification.

GEORGE rmnsniznn; 

